Pedigrees& Genetic Disorders

Show the genetic history of a family

“Genetic Family Tree“

Shows phenotypes one generation to the next

Sometimes shows genotypes from one generation to the next;and sometimes you can figure out the genotype

based on your knowledge of inheritance

What is a Pedigree?

http://nd05.jxs.cz/776/087/f51a5cac71_86805403_o2.png

The Weasley Family Tree

each generation is represented using a Roman Numeral circles are females, squares are males a line connecting two shapes indicated a mating shaded in areas indicate an individual affected by the

trait

Pedigree Example FF= Free hanging earsFf= Free hanging earsff= Attached ears

Ff Ff

FfFfff

ff

FFFf

FfFF FF FF Ff

What do you see?

Pedigree Example

Pedigrees tell the phenotypic/genotypic story:◦ Who bred with who? (i.e. Any new traits

introduced?)◦ What was the relationship between relatives?

(i.e. Third cousins once removed)◦ What traits were passed on? (i.e. Hanging ears or

Sickle Cell Anemia)

So who would cares?

Who cares about pedigrees?

A genetic disorder is a disease that is caused by an abnormality in an individual's DNA. Abnormalities can range from a small mutation in a single gene to the addition or subtraction of an entire chromosome or set of chromosomes. (The University of Utah, 2013)

What is a genetic disorder?

Common Misconception Alert!

Genetic disorders are all

inherited.

– NOT TRUE!

Level 1: Single Gene Disorders◦ Mutation of a single gene cause protein to be

altered or deleted

Level 2: Chromosome Abnormalities◦ Entire chromosomes or large segments are

deleted, duplicated or altered

Level 3: Multifactorial Disorders◦ Mutations in multiple genes, often coupled with

environmental factors

Levels of Genetic Disorders

(The University of Utah, 2013)

(The University of Utah, 2013)

Factors of Genetic Disorders

Environmental Stress Diet Physical/Mental Abuse Drugs and Alcohol Exposure to Radiation,

Pathogens, Toxins and Chemicals

E.g. A person exposed to head injuries may be more likely to develop Alzheimer’s.

Heredity

Family Medical History

◦ 1st, 2nd and 3rd generation

◦ Skipped Generations

◦ Carriers Autosomal Dominant/ Recessive X-Linked Dominant/ Recessive Mitochondrial (paternal mtDNA)

E.g. Huntington’s Disease is an Autosomal Dominant disease, and thus every generations will be affected by it.

Down’s Syndrome: Trisomy 21

Klinefelter Syndrome: XXY

Turner Syndrome: XO

Fragile-X Syndrome: X-Linked Dominant ( FMR1)

Duchenne Muscular Dystrophy: X-Linked Recessive (DMD

gene)

Huntington’s Disease: Autosomal Dominant (HTT gene)

Tay Sachs: Autosomal Recessive (HEXA gene)

Cystic Fibrosis: Autosomal Recessive (CFTR)

Sickle Cell: Autosomal Recessive (HBB gene)

Common Genetic Disorders and Their Mutations

Royal Family Pedigree (X-linked recessive)

Autosomal Recessive Blood Disorder Some Symptoms: anemia, fever, chest pain,

increased risk of infections, especially respiratory infections, death

http://www.youtube.com/watch?v=9AHFHleYwdU

Sickle Cell

Malaria:◦ Vector-borne disease, parasites are transmitted by

mosquitoes through blood◦ Symptoms include fever, chills, flu-like illness, may

cause death◦ In 2010 an estimated 216 million cases of malaria

occurred worldwide and 655,000 people died, most (91%) in the African Region (CDC, 2010)

Sickle Cell◦ Carriers have increased resistance against malaria◦ 60% protection against overall mortality

◦ http://www.youtube.com/watch?v=1fN7rOwDyMQ&playnext=1&list=PLD371690519F378F5&feature=results_main

Sickle Cell and Malaria

Sickle Cell Anemia

= Carriers of the disease= Unaffected Individuals

= Affected by the Disease